Merge pull request #58 from amejiarosario/feature/hashmap

Feature/hashmap

Author: amejiarosario

book/content/part03/hashmap.asc

@@ -301,7 +301,7 @@ Hash Map it’s very optimal for searching values by key in constant time *O(1)*
 .2+.^s| Data Structure 2+^s| Searching By .2+^.^s| Insert .2+^.^s| Delete .2+^.^s| Space Complexity
 ^|_Index/Key_ ^|_Value_
 | Hash Map (naïve) ^|O(n) ^|O(n) ^|O(n) ^|O(n) ^|O(n)
-| Hash Map (optimized) ^|O(1)* ^|O(n) ^|O(1)* ^|O(1)* ^|O(1)*
+| Hash Map (optimized) ^|O(1) ^|O(n) ^|O(1)* ^|O(1) ^|O(n)
 |===
 {empty}* = Amortized run time. E.g. rehashing might affect run time.
 // end::table[]

src/data-structures/maps/hash-maps/hash-map.js

@@ -30,6 +30,17 @@ class HashMap {
     this.reset();
   }
 
+  /**
+   * Reset or reinitialize all values on the hashmap.
+   *
+   * Used for rehashing, clear and initializing the map.
+   *
+   * @param {array} buckets - New bucket.
+   * @param {number} size - The new size of the hashmap.
+   * @param {number} collisions - The number of collisions.
+   * @param {array} keysTrackerArray - The array of keys in insertion order
+   * @param {number} keysTrackerIndex - The last index of keysTrackerArray
+   */
   reset(
     buckets = new Array(this.initialCapacity),
     size = 0,
@@ -273,6 +284,13 @@ class HashMap {
   get length() {
     return this.size;
   }
+
+  /**
+   * Removes all key/value pairs from the Map object.
+   */
+  clear() {
+    this.reset();
+  }
 }
 
 // Aliases

src/data-structures/maps/hash-maps/hash-map.spec.js

@@ -265,7 +265,7 @@ describe('HashMap Tests', () => {
       hashMap.delete('All About That Bass');
       hashMap.set('All About That Bass', 'Meghan Trainor');
       expect(hashMap.keysTrackerIndex).toBe(12);
-      // should hava a hole
+      // should have a hole
       expect(hashMap.keysTrackerArray).toEqual(['Pineapple', 'Despacito', 'Bailando', 'Dura', 'Lean On', 'Hello',
         undefined,
         'Wake Me Up', 'Brother', 'Faded', 'The Spectre', 'All About That Bass']);

src/data-structures/maps/map.spec.js

@@ -138,5 +138,19 @@ mapImplementations.forEach((MapImplementation) => {
         ]);
       });
     });
+
+    describe('#clear', () => {
+      beforeEach(() => {
+        map.set(1, 2);
+        map.set(2, 'dos');
+        map.set(3, 3);
+      });
+
+      it('should work', () => {
+        expect(map.size).toBe(3);
+        expect(map.clear()).toEqual();
+        expect(map.size).toBe(0);
+      });
+    });
   });
 });

src/data-structures/maps/tree-maps/tree-map.js

@@ -133,6 +133,13 @@ class TreeMap {
       yield [node.value, node.data()];
     }
   }
+
+  /**
+   * Removes all key/value pairs from the Map object.
+   */
+  clear() {
+    this.tree = new Tree();
+  }
 }
 
 // Aliases